Rolling-element bearing cages of the above-mentioned type are well known. They are usually comprised of two side rings, which are connected to each other via a number of bridges. The receiving pockets for the rolling elements are formed between the bridges. For lubricating, lubricating grease is supplied in the space between the bearing-inner- and -outer-ring.
In particular with rapidly rotating rolling-element bearings there is the problem that the grease distribution inside the rolling-element bearing is subject to locally strong fluctuations before, during, and after the running-in process. At high rotational speeds, insufficient lubrication can occur in the rolling-element bearing, above all in the sliding contact and thus in the region of the cage pocket geometry. Due to the high centrifugal forces the grease is pumped at correspondingly high rotational speeds towards the outer-ring raceway, furthermore also out of the bearing-inner-ring geometry. It is thus no longer available in the region of the cage pockets (in the region of the bridges and of the side rings).
To date this problem has been countered by an increased amount of lubricant being supplied or by the bearing being relubricated at relatively short intervals. Both measures result in an environmental impact or higher costs.